This proposal embraces a large variety of studies of red cell metabolism, function and production. Methods for the study of red cell biochemistry will be developed and improved. Metabolic parameters such as ATP, 2,3-DPG, and glycolytic intermediates in red cells which are rapidly metabolically depleted and in red cells from patients with hereditary enzyme abnormalities will be correlated with changes in red cell morphology as determined by scanning electron microscopy, and with red cell calcium, red cell lipids, membrane proteins and red cell deformability. The storage of red cells at 4 degrees in a medium containing bicarbonate-adenine-glucose-mannitol-phosphate, and of red cells with the addition of dihydroxyacetone will be studied. Efforts will be made to purify urinary erythropoietin. The uptake of iron by cultured fibroblasts from normal subjects and persons with idiopathic hemochromatosis will be undertaken.